1. Field of the Invention
The present invention relates to an image processor that performs cardiac analysis based upon volume data including an examined chest by X-ray CT.
2. Description of the Related Art
The acceleration of a helical scan and the development of a volume scan using a two-dimensional detector greatly changed the concept of an X-ray computed tomograph from a mere multiplanar imaging device to a volume imaging device. That is, the scan of the volume of an examined body at high speed with short temporal resolution was enabled by the X-ray computed tomograph provided with these scan modes. Together with the practical use of the X-ray computed tomograph provided with such a function, the use in many diagnostic fields unused so far is tried and movement to grope for a completely new diagnostic method is started. For one direction, there is the application to evaluative diagnosis related to a beat of the heart. As a volume scan substantially realizes that the whole heart is continuously scanned in a short cycle together with a segment scan mode, analysis related to the kinetic function of the heart such as the variation in time of the inner wall and the outer wall of a left ventricle and the variation in time of the thickness of a cardiac muscle is enabled.
One of the most important items that influence its precision in the analysis of the cardiac function is to precisely match a cross section to be analyzed with a direction perpendicular to the long axis of a left ventricle for example. It is to enhance precision in further extracting the inner wall and the outer wall of the left ventricle based upon the long axis of the left ventricle. Heretofore, an operator has made an effort to get skillful in these operations so as to enhance precision. The operator manually sets the long axis of the left ventricle and specifies a starting point of the trace of the inner wall and the outer wall of the left ventricle and a search range. Therefore, the workload of the operator increases and in addition, the result of analysis disperses depending upon an operator.